Question

I have problems with $pdo->execute($values).

It works fine if I use $pdo->execute() without $values:

$dsn = sprintf('%s:host=%s;port=%s;dbname=%s', DB_TYPE, DB_HOST, DB_PORT, DB_NAME);
$pdo = new PDO($dsn, DB_USER, DB_PASS, array());
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$sql = 'SELECT * FROM "user" ORDER BY id DESC LIMIT 50 OFFSET 0';
$stmt = $pdo->prepare(trim($sql));
$stmt->setFetchMode(PDO::FETCH_OBJ|PDO::FETCH_PROPS_LATE);
$stmt->execute();

echo "<pre>";
print_r($stmt->fetchAll());
echo "</pre>";

It works fine, but when I want to add values replacement:

$dsn = sprintf('%s:host=%s;port=%s;dbname=%s', DB_TYPE, DB_HOST, DB_PORT, DB_NAME);
$pdo = new PDO($dsn, DB_USER, DB_PASS, array());
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$sql = 'SELECT * FROM "user" ORDER BY ? ? LIMIT 50 OFFSET 0';
$values = array('id','DESC');

$stmt = $pdo->prepare(trim($sql));
$stmt->setFetchMode(PDO::FETCH_OBJ|PDO::FETCH_PROPS_LATE);
$stmt->execute($values);

echo "<pre>";
print_r($stmt->fetchAll());
echo "</pre>";

It doesn’t work. It returns:

SQLSTATE[42601]: Syntax error: 7 ERROR: syntax error at or near “$2”
LINE 1: SELECT * FROM “user” ORDER BY $1 $2 LIMIT 50 OFFSET 0 ^’ in
…

Answer 1

ORDER BY expects a comma-separated list of columns if there’s more than one column in the order by clause